Since a number of cool things are happening in space exploration these days, we'll widen the scope of this thread a smidge. Conversation about all things space exploration are welcome, whether it be from NASA, SpaceX, ULA, Blue Origin, or anyone else. Chances are most of the discussion will still be about SpaceX since they love to make things public and fun, but nothing's off limits. I'll eventually get around to modifying the OP to include resources for other companies too, but in the meantime, feel free to post any cool stuff you run across.
Tim Dodd (Everyday Astronaut) - A "random dude" who got really into space (particularly SpaceX). He's a great resource for simple explanations of this stuff, as well as live hosting launches.
USLaunchReport - Lost of videos of the more mundane stuff (e.g., booster recovery operations). Not a ton of commentary.
NASASpaceFlight - Live hosting of most launches including a ton of video of Starlink operations.
Glossary
Spoiler!
Space discussions tend to get a little bogged down in jargon, so here's a list of terms you might encounter. (Others, please let me know of others that should be added.)
ASDS - Autonomous Spaceport Droneship - The "barges" that they sometimes land rockets on.
Dragon - The cone-shaped capsule that sits at the top of the rocket for ISS-bound launches that holds the cargo (or, in the future, humans).
F9 - Falcon 9, the name of the rocket itself.
FH - Falcon Heavy, the three-booster version.
GTO - Geosynchronous Transfer Orbit, a type of orbit that will eventually result in the satellite orbiting the earth as it turns so that it seems to be in the same spot from the ground (such as DirecTV or Dish satellites). These types of launches are particularly challenging because they require a lot of power to get them into the right orbit, leaving very little fuel left for landing.
HIF - Horizontal Integration Facility - the building near the launch pad where they put all of the pieces of the rocket together before rolling it out to the pad.
ISS - The International Space Station
JRTI - Just Read The Instructions, the name of the "barge" that they land on for west-coast launches.
LEO - Low Earth Orbit, a fairly low orbit shared by many satellites and ISS. These launches usually require less power to achieve the proper orbit, so the first stage can often be landed back on land rather than on a drone ship.
LZ1 - Landing Zone 1, basically a big open slab of concrete at Cape Canaveral where the first stage will attempt to land (for some launches).
NET - No Earlier Than, basically the date they're hoping to launch, but rocket launches have a tendency of getting delayed.
OCISLY - Of Course I Still Love You, the name of the "barge" that they land on for east-coast launches.
RTLS - Return to Landing Site, a mission where the first stage comes back and lands at LZ1.
Starship - SpaceX's next-generation rocket (and spacecraft) that will hopefully one day take us to Mars. Starship is the "second stage" that will carry cargo or people, but also refers to the whole system. (It's confusing, but think of it like the Space Shuttle, which was both the shuttle itself and the entire launch system.)
Super Heavy - The giant booster that will carry Starship to space.
Originally Posted by DaFace:
I just realized the coolest part of that photo. If you zoom in at full resolution....
You can actually see the first stage starting its "flip" while the second stage continues onward. Pretty cool.
I get forward momentum, maintaining energy in a turn, centrifugal force, centripetal force, and all jazz, but after they use the cold-gas release to flip it, I'm having a hard time wrapping my mind around how does a rocket get going back the other way to make it back over land (in the near weightlessness it's in)? At least not without another burn, or unless the flip is more of a slow turn to allow momentum to ultimately send you back the other way? [Reply]
Originally Posted by GloryDayz:
I get forward momentum, maintaining energy in a turn, centrifugal force, centripetal force, and all jazz, but after they use the cold-gas release to flip it, I'm having a hard time wrapping my mind around how does a rocket get going back the other way to make it back over land (in the near weightlessness it's in)? At least not without another burn, or unless the flip is more of a slow turn to allow momentum to ultimately send you back the other way?
While I don't claim to fully understand it myself, I think the key is that there's a lot more force being applied during that boost back burn than you'd think based on the brightness of it. It's burning a TON of fuel during that little arc to turn itself around and start heading back to land. The thrusters flip it around, the main engines are used to make it actually change direction.
I think this diagram is at least reasonably accurate (though it's boosting back further to make it to land).
Also, another thing to keep in mind is that the first stage weighs MUCH less at that point than the original rocket did (given that there's no second stage at all, and a majority of the propellant has already been used up), so it's quite a bit easier to slow down than you might think. [Reply]
Originally Posted by DaFace:
While I don't claim to fully understand it myself, I think the key is that there's a lot more force being applied during that boost back burn than you'd think based on the brightness of it. It's burning a TON of fuel during that little arc to turn itself around and start heading back to land. The thrusters flip it around, the main engines are used to make it actually change direction.
I think this diagram is at least reasonably accurate (though it's boosting back further to make it to land).
Also, another thing to keep in mind is that the first stage weighs MUCH less at that point than the original rocket did (given that there's no second stage at all, and a majority of the propellant has already been used up), so it's quite a bit easier to slow down than you might think.
That makes sense actually. We know they do barge landings because they "don't have the fuel", but that not having fuel might be a combination of pushing a heavier load up, thus not having that amount of fuel to use on the boost back. And I found similar drawings for those barge-based landings, I just didn't find one that was noted-up like that for land-based landings.
Perhaps a trip to SpaceX (to ask questions) would be a wise vacation for me... :-)
Sent from my phone using Tapatalk (so spelling be damned!!!) [Reply]
Also, the next launch will be JCSAT-16, but there's not an exact date for it yet - just "sometime in August." I'll take the countdown clock out of the OP until we have a firm date. [Reply]
It's gonna be a hell of a sight to see, for sure. I'd almost make a vacation down to Florida to watch if it wasn't for the high likelihood of delays. [Reply]
Originally Posted by DaFace:
It's gonna be a hell of a sight to see, for sure. I'd almost make a vacation down to Florida to watch if it wasn't for the high likelihood of delays.
